Overshot loader



y 24, 1966 H. L. ORWIG ETAL 3,252,605

OVERSHOT LOADER 7 Sheets-Sheet 1 Filed March 12, 1963 5 w R N w W mg W WW 4 0M W #4 y 4, 1966 H. 1.. ORWIG ETAL 3,252,605

OVERSHOT LOADER 7 Sheets-Sheet 3 Filed March 12, 1963 m M; w W; E W A ML.

M8324, 1966 H. L. ORWIG ETAL. 3,252,605!

OVERSHOT LOADER 7 Sheets-Sheet 4 Filed March 12, 1963 s Y w W T N Y m m W A 1? 0M L c H4 Y is v \Q mv. Nb O0 May 24, 1966 H. L.ORW1G ETAL OVERSHOT LOADER 7 Sheets-Sheet 5 Filed March 12, 1963 xQE i INVENTORS H L. OQWIG LA. MoLaY 3,252,605 7 Sheets-Sheet 6 OVERSHOT LOADER H. L. ORWIG ETAL May 24, 1966 Filed March 12 INVENTORS h. L. Dew/s BY LA. MOLE) rTop/vsy May 24, 1966 H. L. ORWIG ETAL OVERSHOT LOADER 7 Sheets-Sheet 7 Filed March 12, 1963 INVENTORS 1. 0/? W16 1. 4. MUZBY ATTORNEY United States Patent 3,252,605 OVERSHOT LOADER Herbert L. Orwig, Rochester, and Lloyd A. Molhy, Batavia, N.Y., assignors, byv mesne assignments, to Eaton Yale & Towne Inc., a corporation of Ohio Filed Mar. 12, 1963, Ser. No. 264,520 11 Claims. (Cl. 214-140) This invention relates to a shovel loader of the type known in industry as an overshot loader. Loaders of the particular class utilize a shovel or bucket that is mounted for swinging movement on the loader vehicle so as to bring the bucket from a position at the front of the vehicle where it is loaded, to an upper position rearward of the vehicle where it is dumped. Obviously, the bucket must be manipulated for loading, and must be manipulated for maintaining the load within the bucket until the bucket is carried to its dumping position.

Those skilled in the art fully appreciate that much effort has been made to simplify the effective movement of a shovel loader bucket in a vehicle of the class described. However, so far as we know, no completely satisfactory overshot loader has been developed. We believe that our invention contributes an overshot loader of extreme simplicity in construction while yielding extremely effective operation through novel controls we have conceived.

Thus, as a feature of our invention, we use but two main arms, one at each side of the vehicle, and each of these arms is operated by a large ram that is so pivoted that it may swing effectively while still imparting lifting force to the arms in an efficient manner in all positions of the arms.

As a further feature of the invention, the shovel or I or more rams eifectively positioned between the bucket and the arms.

As one feature of our invention, Weemploy means, which may be in the form of two pumps, for supplying fluid to the main lifting rams for the arms, with means for automatically rendering a part of the fluid supply means or pumps inoperative during a part of the cycle where it is desired that the speed of movement of the arms be relatively slow. As a more detailed feature of this part of the invention, the operator can very simply and without substantial effort, achieve full operating speed. Specifically, this can be accomplished by the mere maintenance of manual pressure on an operating control valve. It is important for a comprehension of this feature of our invention to appreciate the fact that the automatic means will effectively stop the supply of fluid from one ofthe pumps when the arms pass through a predetermined relatively short zone, so that it is only during the movement of the arms through this short zone, that manual pressure must be maintained to prevent the automatic decrease of lifting speed.

As a further feature of the invention, the bucket is moved, after operation of a particular control, to a stabilized position for retaining its load during-swingng movement of the lifting arms. Further, the bucket is automatically brought to a halt in its pivotal movement relatively to the arms when it has reached the particular stabilized position. However, as a feature of our invention, the bucket may be moved in either direction from its stabilized position by manual control, and may by the maintenance of simple manual pressure, be prevented from halting at its stabilized position.

As part of our controls, we utilize manual operating valves of the type that can be moved to neutral position by a particular application of hydraulic pressure. How- 3,252,605 Patented May 24, 1966 ever, the valve will not so move if the movement is opposed by manual pressure. One of those operating valves is the control valve that renders one pump inoperative. Another of those valves is the control for the pivoting of the bucket, and a third operating valve controls the swinging of the lifting arm by the first pump, whether or not the second pump is operative. The three operating valves have handles that are juxtaposed to one another, so that the operator may easily actuate two or more of the valves simultaneously when using merely one hand.

As another feature of our invention, we mount the front axle of our loader for rocking movement to facilitate movement of the loader on uneven ground. At the same time, we provide means for selectively locking the front axle against this rocking movement to stabilize the loader during operation of the various arm and bucket controls. As still another feature, We fix therear axle against rocking movement, so that when the bucket is in the elevated position substantially above the rear axle and the truck in the least stable condition, the fixed rear axle effectively stabilizes the truck against rocking. To provide a very rigid rear axle structure for this purpose,

we preferably mount the wheels directly on the ends of V the rear axle and effect steering by bodily rotating the axle and wheels about a central pivot which is fixed to the loader frame.

Those skilled in the art will fully understand, after reading the description of our invention, that we are able to contribute a very effective overshot loader through the utilization of the particular controls set forth. Thus, we can employ simple swinging arms, and a simple pivoted bucket moving about a single pivot by a single ram. At the same time, we contribute full overshot operation.

As further detailed features of our invention, we utilize hydraulic controls with extremely effective but simple operating means. Thus, it is the effective fluid pressure flowing to a ram that controls the ram, and is in turn efiectively controlled by the arm or bucket the ram is moving.

We have thus outlined rather broad the more important features of our invention in order that the detailed description thereof that follows may be better understood, and in order that our contribution to the art may be better appreciated. There are, of course, additional features of our invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which our disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of our invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from the spirit and scope of our invention, in order to prevent the appropriation of our invention by those skilled in the art.

In the drawings:

FIG. 1 is an elevation of our novel overshot loader, illustrating different positions of the loader bucket;

FIG. 2 is a perspective showing details of the loader bucket and its control cam;

FIGS. 3 and 4 show the lifting arm control cams and their valves;

FIG. 5 is a side view showing parts of our loader in more detail;

FIG. 6 is a diagrammatic view of the hydraulic operating and control circuits of our loader;

FIG. 6A shows an orifice valve that we utilize in our circuits;

FIG. 7 shows in section the manually operated bucket control and arm control valves;

FIG. 8 shows in section the manually operated high speed lift valve;

FIG. 9 shows the construction of the cam actuated valves;

FIG. 10 .shows a perspective view of our loader;

FIG. 11 shows diagrammatically the front axle and axle control circuit of our loader;

FIG. 12 shows in section the axle control valve;

FIG. 13 is a plan view showing the mounting of the rear axle; and

FIG. 14 is a side elev-ational view of the rear axle mounting.

Referring now more particularly to FIG. 1 of the drawings, we construct our novel loader with a main frame 10 on which are front and rear wheels 11, 12, and a lifting arm 13 that supports a bucket 14. Only one side of lifting arm 13 is visible in FIG. 1, and it generally will be sufficient to consider merely that side when we refer to lifting arm 16, because parts of the arm are similar at each side of the loader, as is conventional in loaders of the particular class. In FIGS. 3, 4, 6 and 10, we do indicate the opposed side part of arm 13 by the numeral 113, the parts being connected through a cross member 130. FIGS. 5, 6 and 10.

The front wheels 11 are supported on an axle 91, FIG. 10. An operators cab 15 is supported in position on the truck frame 10 between the side par-ts of lifting arm 13, and almost directly above the axis of the front wheels 11.

The lifting arm 13, or more exactly each side part of the arm, is mounted at its inner end on a pivot 16 that is arranged just above the .rear wheels 12, and that is supported on a portion 17 of the loader frame 10, as indicated in FIG. 1. The lifting arm 13 is somewhat C-shaped, and in lowered position extends in an upward and forward direction from its pivot 16 and then downwardly in front of the axis of wheels 11. A double acting hydraulic lift ram 18 is pivoted at 19 to a portion 20 of the loader frame 10, its piston portion being pivoted at 21 to a rearward portion of arm 13. As best seen in FIGS. 1 and 5, the pivot 19 is arranged on a medial part of the ram 18, so that the ram will rotate through a considerable angle and will cause a more efficient line of force application as it swings lifting arm- 13 about pivot 16. Thus, the line of force of ram 18 is very close to 90 to a line between pivots 16, 21 during that part of the lifting movement when the force is most needed.

Referring to FIG. 10, the loader bucket '14 includes a lower or forward wall .25 that is equipped with a digging blade 26, a relatively wide angular back wall 27, and end walls 28. Three triangular brackets 29, 30, 31, best seen in FIG. 2, are secured to the back wall 27 at one side of the bucket 14. The brackets 29, '30 are connected through a pivot 32 to the outer end of lifting arm 13, as shown also in FIGS. 1 and 5. The brackets 30, 31 extend beyond the pivot 32 and in effect are levers, being equipped with a pivot pin 33 through which a double acting hydraulic tilt ram 34 will act to rotate bucket 14 about pivot 32. The ram 34 is supported on a pivot 35, FIGS. 1 and 5, which is mounted through abracket 36 on the cross member 13a of lifting arm 13. We form on the lifting arm 13 an angular plate 37, FIGS. 2 and 5, that is adapted to be engaged by edges of the bracket 29 so as to act as a stop for the rotating movements of the bucket 14.

It will be appreciated that we have described the construction of the lifting arm 13 and bucket 14 at merely one side of the loader, and that there will be a similar construction at the opposed side of the loader, including.

a further hydraulic lift ram 118 and tilt ram 134. These are shown diagrammatically in FIG. 6.

At this point, we do call attention to the fact that we Referring to FIGS. 3, 4. and 5, we equip the lifting In due course, we shall describe. the manner in.

arm 13 with a pair of control cams which we indicate by the numerals 40, 41. FIGS. 3 and 4 show those cams mounted on the opposed side parts of the arm 13, one of those parts being indicated by the numeral 113, but it is conceivable that both earns 40, 41 may be arranged on either side part of the lifting arm. Each cam scribe the hydraulic circuits of our novel overshot loader. We utilize primary and secondary hydraulic pumps 50, 51 that will be supplied with hydraulic fluid through lines 52, 53 from a reservoir 54. The fluid pressure of primary pump 50 will be applied through a line 55 to a first valve casing 56 in which there is a lift control plunger 57 that is manually operated through a handle 58, and a tilt control plunger 59 that is manually operated through a handle 60. The fluid pressure of secondary pump 51 will be applied through a line 61 to a second valve casing 62 having a high speed lift plunger 63 that is manually operated by a handle 64.

We call attention here to the fact that we arrange the valve plungers 57, 5-9, 63 in aligned parallel relation, with their'handles 5'8, 60, 64 rather closely juxtaposed to one another, so that the operator may rather easily move the plungers simultaneously when using merely one hand. Also, the handles 58, 60, 64 are so mounted on pivots 60a that the lifting of a handle will depress its corresponding plunger.

The valve casings 56, 62 and their plungers have a standard construction that is commercially available, and we believe it will suflice to describe them briefly. Thus, referring to FIG. 7, the first valve casing 56 has an inlet 65 to which the high pressure line 55 is connected. There also is an outlet 66 through which low pressure returns to the reservoir 54, FIG. 6. The lift and tilt control plungers 57, 59 form spool valves, and with both of those plungers in neutral position as shown in FIG. 7,

the fluid will be free to move from inlet 65 through chambers 67,, 68 and 69 to return opening 66, the arrangement being such that the fluid first must pass spool valve 59, and then spool valve 57. A pressure relief valve 70 relieves high pressure from inlet chamber 67 directly to outlet chamber 69 at times when that may be necessary.

As shown in phantom in FIG. 7, there are four hydraulic lines 71, 7.2, 73, 74 connected to further openings in casing 56. High pressure moves from inlet chambers 67 to portions of the tilt control valv 59 through passages, not shown, and valve 59 when moved in either direction from neutral position will direct the high pressure alternately through lines 71 or 72 while allowing low pressure return through the opposed line 72 or 71. The lift control plunger or spool 57 is adapted to direct pressure in a similar manner relatively to lines 73, 74, but can do so only when tilt plunger 59 is in neutral position. That is because the high pressure for lift control valve 57 is supplied from the chamber 68, through passages not shown. As will be understood when considering FIG. 7, chamber 68 will have no appreciable pressure when tilt plunger 59 is in an actuated position. On the lower part of valve housing 56, there are kick out devices 75, 76, each actuated by fluid pressure that may be applied through a line 77 or 78. Should plunger 57 be in position applying high pressure to line 74, kick out device 75 when actuated will return that plunger to neutral position. Similarly, the actuation of kick out device 76 will be effective. when plunger 59 is in position applying pressure to line 72, for returning plunger 59 to neutral position. Each kick out device 75, 76 Will act with moderate power, so that it always is possible to control the position of the lift and tilt pungers 57, 59 through manual pressure, despite actuation of the kick out.

The high speed lift control housing 62 and plunger 63, FIG. 8, are like the housing and plungers we have just described, excepting that in this case, there is merely the one plunger 63. We believe it will be suflicient to say that plunger 63 will direct pressure from pump line 61 alternately to a line 79 or 80, allowing return flow from the opposed line 80 or 79 to an outlet 81 which communicates with the reservoir 54, FIG. 6. There is a kick out device 82 which is responsive to pressure in a line 83, and which is adapted to move plunger 63 to neutral position when that plunger has been .placed in position applying pressure to line 80.

Returning now to FIG. 6, it will be seen that the hydraulic line 73 extends from the first valve housing 56 through an orifice valve 84 which we shall describe at the proper time. From valve 84, line 73 continues to one end of the lift ram 18, line 73 having a branch line 173 that extends also to lift ram 118 at the opposed side of the truck. Line 74 extends from valve housing 56 to lift ram 18, with a branch line 174 to ram 118. Lines 73, 74 and their branches 173, 174 are so connected that the lift valve handle 58 when raised will cause rams 18, 118 to swing the lift arm 13, 113 in an upward and rearward direction. When handle 58 is depressed, the lifting arm will swing toward its lowered position in front of the loader.

Line 71 extends from valve housing 56 to a branched connection with corresponding ends of the tilt rams 34, 134. Line 72 similarly extends to the :tilt rarns, the arrangement preferably being such that the tilt control handle 60 when raised will cause the rains 34, 134 to tilt the loader bucket 14 in a forward dumping direction, handle 60 when depressed causing bucket 14 to tilt rearwardly.

Still considering FIG. 6, hydraulic line 80 extends fro-m the second valve housing 62 to a connection with the line 74. Line 79 extends from housing 62 to a connection which is between the orifice valve 84 and the lift rams 18, 118 on line 73. The connections to which lines 79, 80 extend are so arranged that the high speed control handle 64, when moved in the same direction as is the lift handle 58, will add the fluid pressure of the secondary pump 51 to the pressure already applied to lines 73, 74 through the valve housing 56, and in the same direction. Thereby, it will be appreciated that operation of the valve handle 64 is adapted to increase the speed at which the lifting arm 13 swings.

The orifice valve 84, to which we have already alluded, has a valve member 84a, FIG. 6A, that is normally held in seated position by a coil spring 84b. It will be seen that valve member 84a has an orifice 84c. We so arrange orifice valve 84 that the fluid pressure will move valve member 84:: from its seat so as to permit a relatively free flow of fluid through line 73 toward the lift rams 18, 118, that being the direction in which the fluid moves to swing the arm forwardly and downwardly. When the arm 13 swings in a lifting direction, valve 84a moves to seated position in which the fluid returning through line 73 must move through the orifice 84c. However, orifice 840 is so designed asto otfer little resistance to the relatively low rate of return flow when the lifting operation is merely due to the actuation of control handle 58. Orifice 84c does offer a very considerable resistance to a higher rate of return flow, and we shall describe the effect of that arrangement, referring to FIG. 6.

Thus, during the low speed swinging of lifting arm 13, the fluid can move easily through line 73, 74 and orifice valve 84 to the first valve housing 56. When there is high speed swinging of lifting arm 13 in upward and rearward direction, the added flow which is due to the operation of secondary pump 51 also can move freely in lines 79 and 80. However, if we now assume that the operator of the loader moves the high speed handle 64 to neutral,

the return flow through line 73 must move through the orifice valve 84. Since that valve opposes a high rate of how, it will be fully effective to slow the upward and rearward swinging of lift rams 18, 118, and therefore the lifting arm 13, to a speed which is consistent with the pressure that is applied merely through the primary pump 50. Thus, when the operator wishes to change from high speed-to low speed movement, the lifting arm 13 will not swing rapidly merely because of its momentum.

We shall now call attention to the fact that the lift kick out line 77 extends to the cam actuated valve 45, the high speed kick out line 83 extends to the cam actuated valve 46, and the tilt kick out line 78 extends to the cam actuated valve 39. Referring first to the valve 39, it will be seen that valve 39 is adapted to be supplied with fluid pressure through a line 85 which is connected to the forward tilt pressure line 72. Also, it is the function of valve 39 to stop the operation of a ram through utilization of the pressure being applied to the ram and effecting theoperation of the ram. Thus, a return line 86 extends from valve 39 to the fluid reservoir 54. Valve 39 is shown in detail in FIG. 9 as having a spring-biased plunger 39a equipped with a roller 39b through which the plunger can be depressed. Valve 39 normally holds the kick out line 78 in communication with return line 86, but when actuated through depression of plunger 39a, will be effective alternately to place line 78 in communication with the forward tilt pressure line 85. The cam 38 is so arranged as to actuate valve 39 when the lifting arm 13 is in a predetermined overhead position and the bucket 14 is in a predetermined tilted position relatively to the arm. 13.

The value of this arrangement willbe understood when it is realized that the bucket of an overshot loader may tend to spill its contents as it swings overhead. To prevent spilling, the operator of the loader will move the tilt control handle 60 to tilt bucket 14 forwardly through operation of tilt ram 34. Normally the operator will leave the handle 60 in actuated position so that bucket 14 will continue to tilt forwardly as arm 13 swings rearwardly. It will be recalled that the lift valve plunger 57 will not he eifective to apply lifting pressure while tilt plunger 59 is actuated, but lifting .pressure still can be appliedthrough operation of the high speed lift plunger 63. When the bucket 14 has tilted forwardly to a particular position relatively to arm 13, cam 38 will actuate valve 39, so that the fluid pressure which then is present in line 85 will act through line 78 to actuate the kick out 76, returning the tilt valve plunger 59 to neutral position. That causes the bucket 14 to stop its tilting in a position which will be effective to retain the contents of the bucket as arm 13 swings further rearwardly. If we assume that the operator has previously left the lift valve plunger 57 in actuated position, the movement of tilt valve plunger 59 to neutral now will make plunger 57 again elfective to apply pressure to lift ram 18 so that the arm 13 will resume its lifting movement.

The valve 46 is connected through a line 87 to the lifting pressure line 74 and also is connected through a return line 88 to the fluid reservoir 54. Valve 46 is constructed like valve 39, normally connecting the kick out line 83 to return line 88, but valve-46 when actuated will place kick out line 83 in communication with line 87. As indicated in FIG. 5, cam 41 is so arranged on the side part 113 of the lifting arm as to actuate valve 46 when arm 13 swings rearwardly to a position somewhat short of its full dumping position. That will cause the high speed control plunger 63 to return to neutral position if it has been placed in lifting position, the orifice valve 84 then being effective to slow the rearward swinging of the arm.

Valve 45 is like valves 39 and 46, and is connected to the lifting pressure line 74 through a line 89, FIG. 6.

A return line 90 connects valve 45 to fluid reservoir 54.

The cam 40 is so positioned on lifting arm 13, FIG. 5,

as to actuate valve 45 as arm 13 moves to rearward dumping position, shown at 13R in FIG. 1. That will cause the lift plunger 57 to return automatically to neutral, stopping the movement of lifting arm 13 when arm 13 reaches full rearward dumping position. It will be appreciated that the lifting rams 18, 118 may be formed with hydraulic cushions of a usual type so as to cushion the movement of arm 13 to dumping position.

To effect movement of the lifting arm 13 and the bucket 14 in the opposed directions, that is forward swinging of arm 13 or rearward pivoting of bucket 14, the operator will merely move the operating valve plungers 57, 59, 63 in the appropriate directions as he may wish. The kick out devices 75, 76, 82 will not then act and the control will merely be manual.

From the description we have made of the valve plungers 57, 59, 63, it will be appreciated that the operator of the loader can move those plungers in either direction at anytime, or hold them against movement, so as to have full control of the operation of the bucket 14 and lifting arm 13. Thus, for example, should the operator wish to tilt the bucket 14 in a way that conflicts with the operation of the automatic kick out device, he may very readily do so. In fact, he may tilt the bucket 14 at any time and in either direction that he may choose, as when he wishes to effect a front dumping operation, that kind of dumping being indicated in dot and dash lines at 14D in FIG. 1.

' As indicated in FIG. 6, all of the manual control handles 58, 60 and 64 are so mounted as to be positioned close to one another, which enables the operatorvery easily to effect the control that he desires, while achieving safe operation of the loader.

In FIG. 11 of the drawings, we show in more detail the front axle 91 of our loader, together with our novel axle control. The axle 91 is supported for rocking movement on a pivot 92 that is mounted on a front cross member 93 of .the loader frame 10. As will be appreciated, the rocking of the axle 91 will facilitate the movements of our loader when it operates on uneven ground. We

' particularly utilize a hydraulic ram 94 that will control the rocking of axle 91. The ram 94 has a cylinder 95 pivoted through a pin 96 on one side of the frame 10, and a piston '97 that is pivoted to a-bell crank lever.98. A pivot 99 supports the lever 98 for rotation relatively to the opposed side of frame 10. Bell crank lever 98 is also connected through a link 200 to an end portion of axle 91. The ram piston 97 then will move in cylinder 95 as axle 91 rocks on its pivot, as will be understood.

Hydraulic lines 201, 202 lead from opposed ends of ram cylinder 95 to a valve 203, shown in detail in FIG. 12. Valve 203 has separate passages 204, 205 through which each line 201, 202 normally communicates with a corresponding line 206, 207 which leads to the hydraulic reservoir 54. The fluid then can move in each of the lines 201, 202, enabling the ram piston 97 to move so that axle 91 can rock freely on its pivot 92. The valve 203 includes a plunger 208 that is effective when depressed to close each passage 204, 205.

Our loader is equipped with a usual type of brake control 209, FIG. 11, that will be effective when a pedal 211 is depressed to direct fluid pressure through a line 210 to apply the loader brakes, not shown. In our invention, we also direct the fluid pressure from the brake control 209 through a line 212 to a pressure actuated plunger 213. That plunger 213 will act against the valve plunger 208 and will move plunger 208' to position closing the passages 204, 205, when the operator of the truck depresses pedal 211.

With passages 204, 205 closed, fluid cannot move in the ram lines 201, 202, and therefore will lock the hydraulic ram 94. We prefer to install pressure relief valves 214, 215, on corresponding ram lines-201, 202. A discharge from either of those valves will move through a line 216 toward the reservoir 54.

Because ram 94 will be locked when the pedal 211 is depressed, it will be seen that the axle 91 cannot rock on its pivot 92 while the loader brakes are applied. The operator of the loader normally will holdthe brakes applied during the digging and dumping operations of the loader, and therefore the axle '91 will automatically be locked and will effectively stabilize the loader at those times when stability is most to be desired.

When the fluid locks the ram 94, the relief valves 214, 215 will prevent a development of excessive pressure in the ram 94, as might happen under extreme conditions. One or the other of the relief valves 214, 215 will relieve the pressure partially, but not enough to affect the stability of the loader to any considerable degree. While a relief of pressure may allow some slight movement of the axle, sufficient pressure will be retained in the ram 94 to lock the axle 91 after that movement.

To allow the operator to lock the front axle 91 against v and is actuated by a lever 219.

To further stabilize the loader, particularly when the bucket is in an elevated position substantially over the rear axle 220, we fix the rear axle 220 against rocking movement, while allowing bodily rotation of the axle to effect steering of the loader. As shown in FIGS. 13 and 14, the rear wheels 12 are rotatably mounted on the outer ends of the rear axle 220 and the rear axle 220 is pivotally mounted through a bracket 221 on upper and lower vertical pivots 222, 223 which are secured to the main frame 10. By this arrangement, the axle 220 and wheels 12 may rotate bodily about the pivots 222, 223 to effect steering of the loader, while at the same time the axle and Wheels are fixed against rocking movement. Such steering of the rear axle 220 is conveniently effected through hydraulic rams 224, 225 which are provided on opposite sides of the loader and are pivoted at one end to the truck frame 10 and at the other end to the axle 220. Thus, through extension of one ram and contraction of the other, the rear axle 220 and wheels 12 may be rotated about the pivots 222, 223 to effect steering of the loader.

The wheels 12 are driven from a differential 226 which is carried by the axle 220 and the vertical spacing of the two pivots 222, 223 allows a drive shaft 227 to extend to the differential 226. The drive shaft 227 is connected at one end to the differential 226 by a universal joint 228 and connected at the other end to a transmission 229 by a similar universal joint 230, whereby the rear axle 220 rlnay be steered while power is supplied to drive the wheels From the description that we have made, we believe that the operation and the advantages of our novel overshot loader will be clearly understood. We believe, therefore, that those persons who are skilled in the art will understand the very considerable value of our contribution, and that the merits of our invention will be fully appreciated.

We now claim:

1. In a combination of the class described, a main frame, a main arm pivoted on said main frame, a hydraulic ram for swinging said arm, a bucket pivoted to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic fluid under pressure, a pair of operating valves movable between a first position for directing the fluid to said hydraulic rams to swing said arm and said bucket and to pivot said bucket and a second position shutting off the flow of fluid to said rams, control means associated with said bucket and actuated when said arm and bucket are each moved by both said 9 rams to a predetermined relative position for moving one of said operating valves to its second position from its first position to stop pivotal movement of said bucket relatively to said arm by said pivot ram while said hydraulic ram is adapted to continue the swinging of said arm, and

manual means over-riding said control means for holding said one of said operating valves in its first position during the time period said bucket and arm are in said predetermined relative position.

2. In a combination of the class described, a main frame, a main arm pivoted on said frame, a hydraulic ram for swinging said arm, a bucket pivoted to said arm, a pivot rain for pivoting said bucket relatively to said arm, a pair of pumps for supplying fluid under pressure to said rams, an operating valve for each pump movable between a first position for directing fluid to said hydraulic ram to swing said arm and a second position shutting off the flow of fluid to said hydraulic ram, hydraulic control means associated with said main arm and actuated by fluid pressure flowing to said hydraulic ram when said arm is swung to a predetermined medial position relatively to said main frame for moving one of said operating valves to its second position to stop flow of fluid from one of said pumps to said hydraulic ram to slow down the speed of swinging of said arm, and a second control means operably connected to said main arm and actuated when said arm is swung to a second predetermined position for moving the other of said operating valves to its second position to stop flow of fluid from the other pump to said hydraulic ram.

3. In a combination of the class described, a main frame, a main arm pivoted on said frame, a hydraulic ram for swinging said arm, a bucket pivoted to said arm, a pivot ram for pivoting said bucket relatively to said arm, a pair of pumps for supplying fluid under pressure to said rams, an operating valve for each pump movable between a first position for directing fluid to said hydraulic ram to swing said arm and a second position shutting off the flow of fluid to said hydraulic ram, hydraulic control means operably connected to said main arm and actuated by fluid pressure flowing to said hydraulic ram when said arm is swung to a predetermined medial position relatively to said "main frame for moving one of said operating valves to its second position to stop flow of fluid from one of said pumps to said hydraulic ram to slow down the speed of swinging of said arm, manual means over-riding said control means for opposing actuation of said control means by the fluid pressure whereby to hold said one of the operating valves in its first position during the time period said arm is in said predetermined medial position, and a second control means operably connected to said main arm and actuated when said arm is swung to a second predetermined position for moving the other of said operating valves to said second position to stop flow of fluid from the other pump to said hydraulic ram.

4. In a combination of the class described, a main frame, a main arm pivoted on said main frame, a hydraulic ram pivoted to a point on said arm for swinging said arm, pivot means permitting said ram to rotate on the main frame at a point so located intermediate the length of the ram that the ram will act substantially at 90 to the arm as the arm swings on its pivot means, a bucket pivotally attached to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic fluid pressure, a pair of operating valves movable between a first position for directing fluid pressure to said rams to swing said arm and bucket and to pivot said bucket and a second :position shutting oif the flow of fluid to said rams, cam means mounted on said bucket, and control means operablyrnounted on said main arm adjacent said cam means and actuated by said cam means to move one of said operating valves to its second position whereby to stop pivotal movement of said bucket relatively to said arm by said pivot ram when said ram has pivoted the bucket to a predetermined position.

5. In a combination of the class described, a main arm pivoted on said main frame, a hydraulic ram for swinging said arm, a bucket pivotally attached to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic fluid pressure, a hydraulic circuit receiving hydraulic fluid pressure and supplying said rams three operating valve plungers in said hydraulic circuit aligned in parallel relation to each other, actuating means whereby two of said valve plungers when actuated direct fluid pressure to said rams to swing said arm and bucket and to pivot said bucket, additional means whereby the third plunger when actuated directs further fluid pressure to said hydraulic ram to swing its arm and bucket at a faster rate, and three handles mounted in juxtaposed relation to one another for actuating said three parallel plungers.

6. In a combination of the class described, a load actuating hydraulic ram, a load member pivotally moved by said ram, a source of hydraulic fluid under pressure for operating said ram, an operating valve movable 'between a .first position for directing a flow of fluid pressure from said source to said ram to move said load and a second position shutting off the iiow'of fluid to said ram to stop movement of said load, hydraulically actuated means in juxtaposition with said operating valve and responsive to a source of fluid pressure for moving said operating valve from said first position to said second position, a control valve operably connected with said load member and positioned to receive a portion of the pressure fluid directed to said load actuating ram, said control valve being formed so that normally it refuses to accept a flow of the fluid pressure, and control means associated with said control member for actuating said control valve to accept a flow of the pressure received and to provide said source of fluid pressure to said hydraulically actuated means to move said operating valve to said second position.

7. In a combination of the class described, a main arm, a hydraulic ram for swinging said arm, a bucket pivotally connected to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic fluid under pressure for said hydraulic ram and said pivot ram, an operating valve movable between a first position for directing the fluid pressure to said pivot ram to pivot said bucket and a second position shutting off the flow of fluid pressure to said pivot ram, .3. control valve operably mounted on said arm, control means extending from said bucket for actuating said control valve when said bucket is pivoted to a predetermined medial position relatively to said control valve and said arm, hydraulically actuated means in juxtaposition with said operating valve and responsive to said control valve for moving said operating valve to said second position, operable means whereby the actuation of said control valve by said control means effects the operation of said hydraulically actuated means to move said operating valve to said second position from said first position to stop pivotal movement of said bucket, and manual means operably connected with said operating valve for bolding said operating valve in said first position during the time period said bucket is in said medial positon.

8. In a combination of the class described, a main arm, a hydraulic ram for swinging said arm, a bucket pivotally connected to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic trol means extending from said bucket for actuating said control valve when said bucket is pivoted to a predetermined medial position relatively .to said arm to direct a portion of said fluid pressure to said hydraulically actuated means to move said operating valve from said first position to said second position to stop pivotal movement of said bucket, and manual means operably connected with said operating valve for overriding said hydraulically actu-ated means permitting said operating valve to remain in said first position during the time period said bucket is in said medial position.

9. In a combination of the class described, a main arm, a hydraulic ram for swinging said arm, a bucket pivotally connected to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic fluid under pressure for said hydraulic ram and said pivot ram, an operating valve movable between a first position for directing fluidpressure to said pivot ram to pivot said bucket and a second position shutting ofi the flow of fluid p-ressure to said pivot ram, hydraulic control means in juxtaposition with said operating valve and actuated by a portion of the fluid pressure flowing from said source to said pivot ram when said bucket is pivoted to a predetermined medial position relatively to said arm for moving said operating valve to said second position from said first position to stop pivotal movement of said bucket, and manual means operably connected with said operating valve for overriding said hydraulic control means and permitting said operating valve to remain in said first position during the time period said bucket is in said medial position.

.10. In a combination of the class described, a main frame, a main arm pivoted on said main frame, a -hydraulic r-am for swinging said arm, a bucket pivotally connected to said arm, a pivot ram for pivoting said bucket relatively to said arm, a source of hydraulic fluid under pressure for said hydraulic ram and said pivot ram, an arm operating valve and a bucket operating valve movable between a first position for directing fluid pressure to said rams to swing said arm and said bucket and to pivot said bucket and a second position shutting off the flow of fluid to said rams, diverting means on said bucket operating valve shutting ofi the flow of fluid to said hydraulic ram when said bucket operating valve is in its first position, said arm operating valve holding the arm in its position prior to operating said pivot ram and being ineflective for moving said arm while the pivot ram operates, control means operably mounted on said arm and actuated by an actuator mounted on said bucket when said arm and bucket are each moved by both said rams to a predetermined relative position for moving said bucket operating valve to said second position from said first position t-o stop pivotal move ment of said bucket relatively to ,said arm by said pivot ram, and said diverting means on the bucket operating valve then allowing fluid flow to said hydraulic ram for continuing the upward-swinging of said arm.

11. In a combination of the class described, a pivotally mounted load bucket, a bucket tilting hydraulic ram, a source of hydraulic fluid under pressure for said tiltin'g ram, an operating valve movable between a first position for directing a flow of fluid pressure from said source to said ram to pivot said bucket and a second position shutting 011? the flow of fluid to said ram to stop pivotal movement of said bucket, control means including first and second valve means, said first valve means operably connected with said arm and actuated by an extension of said bucket when said bucket is moved by said ram through a predetermined zone, said second valve means responsive to pressure diverted by said first valve means and operably connected to said operating valve for moving said operating valve to said second position from said first position to stop pivotal movement of said bucket, and manual means for overriding said second valve means whereby said operating valve is permitted to remain in said first position during the time period said bucket is in said predetermined zone.

References Cited by the Examiner UNITED STATES PATENTS 2,732,963 1/ 1956 Grubich 214- 2,742,298 4/1956 Witzel 280-611 2,789,712 4/ 1957 Christensen 214-140 2,904,341 9/1959 Heitshu 280-611 2,936,086 5/1960 Pueschner et al. 214-140 3,019,922 2/1962 Webster 214-140 3,028,925 4/1962 Baudhuin et al. -792 3,945,845 7/1962 Hackett et al. 214-140 3,075,603 1/1963 Baudhuin 180-792 3,076,572 2/1963 Schlemmer 214-140 3,086,786 4/1963 Tuczek 280-611 3,092,201 6/1963 Bier 180-792. 3,148,791 9/ 1964 Kampert 214-140 GERALD M. FORLENZA, Primary Examiner.

HUGO O. SCHULZ, Examiner.

A. GRANT, Assistant Examiner. 

1. IN A COMBINATION OF THE CLASS DESCRIBED, A MAIN FRAME, A MAIN ARM PIVOTED ON SAID MAIN FRAME, A HYDRAULIC RAM FOR SWINGING SAID ARM, A BUCKET PIVOTED TO SAID ARM, A PIVOT RAM FOR PIVOTING SAID BUCKET PIVOTED TO SAID SAID ARM, A SOURCE OF HYDRAULIC FLUID UNDER PRESSURE, A PAIR OF OPERATING VALVES MOVABLE BETWEEN A FIRST POSITION FOR DIRECTING THE FLUID TO SAID HYDRAULIC RAMS TO SWING SAID ARM AND SAID BUCKET AND TO PIVOTA SAID BUCKET AND A SECOND POSITION SHUTTING OFF THE FLOW OF FLUID TO SAID RAMS, CONTROL MEANS ASSOCIATED WITH SAID BUCKET AND ACTUATED WHEN SAID ARM AND BUCKET ARE EACH MOVED BY BOTH SAID RAMS TO A PREDETERMINED RELATIVE POSITION FOR MOVING ONE OF SAID OPERATING VALVES TO ITS SECOND POSITION FROM ITS FIRST POSITION TO STOP PIVOTAL MOVEMENT OF SAID BUCKET RELATIVELY TO SAID ARM BY SAID PIVOT RAM WHILE SAID HYDRAULIC RAM IS ADAPTED TO CONTINUE THE SWINGING OF SAID ARM, AND MANUAL MEANS OVER-RIDING SAID CONTROL MEANS FOR HOLDING SAID ONE OF SAID OPERATING VALVES IN ITS FIRST POSITION DURING THE TIME PERIOD AND BUCKET AND ARM ARE IN SAID PREDETERMINED RELATIVE POSITION. 